It's hard to date the birth of email, a communications medium that grew from the melting pot of the various proto-internets of the 1970s. But if one has to be picked, 1 August 1982 is as good as any.

That was when Jon Postel, one of the fathers of the internet, published RFC 821, a technical paper laying out a standard called Simple Mail Transfer Protocol, or SMTP.

More than 30 years on, that standard is still in use. But despite tweaks along the road, it hasn't been able to keep up with all that we demand from a communications medium in the 21st century. Some of that relates to simple problems with the user experience: email doesn't fail gracefully, as anyone who's received an arcane "delivery has failed" message after mistyping an address knows, and it's far too easy to fool recipients into thinking an email was sent by someone else.

But the biggest difference between the internet in 1982 and the internet in 2013 is the need for security; and that's something which email barely addresses.

More than a handful

"You have to remember that the email protocols that we’re using today were developed when there were only a handful of people on the internet – back then it was called DARPANET – and everybody trusted everybody else," says Ladar Levison, the founder of secure email service Lavabit.

“Security was never baked into the protocols, it’s really become an afterthought. And as a result, messages are passed over the internet in plaintext. It’s hard to develop a system which is backwards compatible but is secure by default. In fact, it’s impossible.”

Levison learned that the hard way. Lavabit was an attempt to make email secure by offering users the ability to encrypt their data even while it was stored on his servers. It was popular in the security community, and ended up being used by Edward Snowden, the NSA leaker.

But that led to attention from the government, and Levison couldn't fight it. Faced with a fine of $5,000 for every day he didn't hand over the keys to his encryption, he complied, and then immediately shut down the service to prevent his users' data being compromised.

"This experience has taught me one very important lesson," he wrote at the time: "Without congressional action or a strong judicial precedent, I would strongly recommend against anyone trusting their private data to a company with physical ties to the United States."

Shortly after Lavabit closed its doors, a second secure email service followed. Secure communications company Silent Circle shut down fearing that the legal pressure Lavabit would face could be turned to them next.

"We were sitting on metadata [information about emails, such as sender, recipient and time of delivery], so we knew it was only a matter of time before someone would come to us," says Mike Janke, Silent Circle's co-founder and chief executive. "Email was different – the rest of our products have no metadata, no IP logging, no way – but email was fundamentally broken."

"Somebody's in a heap of trouble"

What led Janke to declare email broken is the one security flaw it has which simply cannot be fixed. In order for messages to reach their recipient, a certain amount of metadata must be sent without any encryption.

Think of it as though you're sending a letter. No matter how secure the envelope is, if you don't write the address on the front in such a way that every postal worker can read it, your letter isn't going to arrive.

The information that accompanies emails is normally innocuous: things like the recipient's address, time of delivery, and the address of the sender. But even that can cause trouble.

"What's happened more recently is just that everyone has become aware that metadata is becoming increasingly important, that the message headers mean a lot," says Phil Zimmermann. He is another co-founder of Silent Circle, but he has an earlier claim to fame as the creator of PGP (Pretty Good Privacy) a popular method for encrypting the contents – but not the metadata – of emails.

PGP was created in 1991, and what it does, it does well: 22 years later, there is still no indication that any security service in the world can break it. But while PGP can render the message itself unreadable, it can't do anything about the message's metadata. And now Zimmermann thinks that is a problem.

"You're a journalist for the Guardian, you know that the Guardian sometimes writes stories that are of great interest to intelligence agencies. Well, what if the intelligence agencies want to see if a journalist at the Guardian is talking to a particular sensitive source? All you have to do is find that so-and-so, some government employee, is talking to some journalist at the Guardian. Then somebody's in a heap of trouble."

Even outside of sensitive situations like that, email metadata can still represent a security issue, because what it represents in aggregate can be a very different thing to what any individual email says. Collect enough metadata together, and you have a complete picture of someone's friendship networks, sleeping patterns, and working hours, all without reading a single email.

"I have a design for a new system."

If email can't be fixed, it must be replaced. A new service, built from the ground up with security in mind, could overcome the problems that toppled Lavabit and Silent Email.

"We met with Ladar first at a privacy conference in Seattle," says Jon Callas, the chief technical officer of Silent Circle. Like Zimmermann, Callas has a pre-Silent Circle claim to fame, as the creator of PGP Universal, which lets companies host PGP-enabled email in the cloud.

"Ladar gave me some notes that he'd had on how to do a more secure email system. I wrote Ladar back and said that I think that email as it exists today is hopelessly broken, but I have a design for a new system."

Before Levison and Callas spoke in Seattle, Dark Mail had been intended to as a Silent Circle product, following on from the company's encrypted text messaging and phone calling services. But their discussion led to a grander aim.

"Ladar liked the ideas," Callas says, "and we had some other phone calls and talked about how we could take the idea and turn it into an infrastructure that many companies could do. We thought it would be even better to open it up to the whole world."

"I didn’t want my daughter growing up in a world like that."

The first time I met Janke, Silent Circle's chief executive, he was wearing a FitBit, one of a new wave of personal fitness monitors. Given how deep he is in the (necessarily) paranoid world of cyber-security, it seems perverse that he would strap on a black, wristwatch-sized band that monitors his movements, location and even whether his sleep is restful or turbulent.

"My daughter bought it for me for my birthday," he explained. "I’m also good friends with the developer, and I’m also a geek, so I love to try things out. I tried out the Nike Fuelband for a month – Jon Callas and I were the among the first 72 people on the Pebble watch. I wore that for a couple of days and it annoyed me so much I sold it on eBay, it was unbelievable.

"I love the biohacking to exercise, but dear God I don’t want that shared with anybody on a database. Right? So I don’t want to download anything to an app. Fitbit works … you can stop it doing that, I have, but it minimises what I can do with the app.

"I have to have very good digital hygiene. I have throwaway phones, throwaway iPads, I have two different MacBooks. Do I want to do that? No. I mean, that’s not anything I ever viewed as the way I ever really want to live and enjoy technology. But the deeper you go down the rabbit hole, the more you begin to see where it can go."

That sort of "paranoia" – as he himself describes his attitude to technology – fits better with his company's mission than the gadget geek side of him does. But it seems like it would have clashed with his previous job, as a US Navy SEAL sniper. Instead, he says that's the reason he moved into cybersecurity in the first place.

"I first saw the massive surveillance capabilities with my travels around the world as a SEAL … It never clashed with my role. In fact, it just heightened it. Then, as a business man, I saw how business secrets and IP was stolen in every hotel wifi around the world – and yet the general public ignored it. I didn’t want my daughter growing up in a world like that."

By virtue of the business they're in, Janke and Silent Circle now straddle the gap between nations and the underworld. "We have three customer bases. A lot of them are private citizens, human rights groups and journalists, who just don't want the government eavesdropping on their conversations."

Others are governments. Janke proudly recounts how the firm had to turn off some security features so that the US government could even see the traffic in order to verify it was secure enough for the military to use.

And then there are businesses. "We started to get an awful lot of calls from law firms in South East Asia, in the span of a month," he says of one such group. "It turns out that in that area, law firms are allowed to hack each other. And that information can be used in court. So if I'm being sued, I pick the law firm that has the best hacking group."

But all of those groups pale compared to the goal for Dark Mail: everyone. "We will be successful if, in three years , 50% of the world's emails are sent through this Dark Mail architecture."

"Security should be the default of architecture. If you choose to use a free service like a map service, you should know what you are giving up. For me, I'm fine if Google knows my wife and I were searching for a new restaurant and how to get to it; I'm not fine with them mining every one of my personal texts, emails and searches. Individual citizens the world over should have the ability to decide what they want to share and what they don't."